<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>23_布局技巧2</title>
    <style>
        .outer {
            width: 400px;
            height: 400px;
            background-color: gray;
            text-align: center;
            line-height: 400px;
        }
        .inner {
            background-color: orange;
            font-size: 20px;
        }
    </style>
</head>
<body>
    <div class="outer">
        <span class="inner">出来玩啊？</span>
    </div>
</body>
</html>